Rotary kiln head waste heat utilization system for metallurgical pellet production

Abstract

The invention belongs to the technical field of smelting rotary kilns, and particularly discloses a rotary kiln head waste heat utilization system for metallurgical pellet production, which comprises a heat storage cavity and an induced draft fan, the heat storage cavity is connected with a heat conduction pipe, the heat conduction pipe is connected with the induced draft fan, the other end of the induced draft fan is connected with a heat conduction pipe, and the heat conduction pipe is connected with a small ball roller screen. The existing rotary kiln preheating utilization device has the problems that only waste heat of a kiln body is utilized, waste heat of a kiln head is still not utilized, a circulating water heat conduction component and other structures are utilized to exchange heat for multiple times, and the waste heat utilization efficiency is low. Heat dissipated from the periphery of the kiln head is concentrated on the surface of the kiln head through the heat storage cavity, the heat in the heat storage cavity is led to the small ball roller screen through the heat conduction pipe and the heat conduction pipe by the induced draft fan, pellets on the small ball roller screen can be preheated, and therefore the heating time or the heating temperature of subsequent drying and roasting is shortened; and normal-temperature air obtained after heat exchange can be used for cooling other equipment, so that the energy-saving effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of smelting rotary kilns, and in particular to a rotary kiln head waste heat utilization system for metallurgical pellet production. Background Art

[0002] The roasting and consolidation process of pellets in the pelletizing plant is completed in the rotary kiln. The pellets preheated by the chain grate are fed into the rotary kiln through the shovel plate and the feeding chute. While rolling along the periphery of the rotary kiln, they move axially toward the kiln head. A specially adjusted telescopic coal powder burner is installed at the kiln head, and the flame length is adjusted by adjusting the ratio of air and coal burning. At the same time, the hot exhaust gas of nearly 1100℃ in the first cold section of the ring cooler is introduced into the kiln head cover as secondary air. To ensure the required roasting temperature in the kiln. The pellets are mainly subjected to heat radiation in the kiln, and they are roasted while rolling, so that the pellets are roasted evenly. The roasted pellets are unloaded into the receiving hopper of the ring cooler through the chute and fixed screen in the rotary kiln head cover. The surface temperature of the rotary kiln head cover is also 250-350℃, sometimes higher. When a large amount of waste heat is wasted, the thermal pollution of the surrounding environment is also increased. Because the pellets need to be oxidized and roasted, the heat provided by the combustion of pulverized coal not only supplies the production, but also has a lot of heat source radiation. The heat radiated outward through the refractory material is not effectively recovered and utilized.

[0003] Patent document CN218270139U discloses an energy-saving device for utilizing waste heat of a rotary kiln. By setting an insulation chamber on the outside of the kiln body, the heat emitted from the periphery of the kiln body is concentrated on the surface of the kiln body for heating the circulation components. The support frame is used to support the bearing plate, and the bearing plate is used to place the circulation components. The heat emitted from the kiln body is concentrated by the heat-conducting components, and the hot air moves upward and is transmitted to the circulation components. The circulation components can absorb the heat and reuse it in other areas.

[0004] The above structure only utilizes the residual heat of the kiln body, while the residual heat of the kiln head is still not utilized. In addition, the heat is exchanged multiple times using structures such as circulating water heat-conducting components, and the utilization efficiency of the residual heat is low. Summary of the invention

[0005] The object of the present invention is to provide a method for solving the problem that the waste heat at the kiln head is not utilized and the waste heat utilization efficiency is low.

[0006] To achieve the above-mentioned purpose, the basic scheme provided by the present invention is: a rotary kiln head waste heat utilization system for metallurgical pellet production, including a heat circulation system and an air circulation system, the heat circulation system includes a heat storage chamber and a first induced draft fan, the heat storage chamber is connected to a heat conduction pipe, the heat storage chamber is connected to the air inlet of the first induced draft fan through the heat conduction pipe, the air outlet of the first induced draft fan is connected to a small ball roller screen through the heat conduction pipe, the air circulation system includes a second induced draft fan, the second induced draft fan is connected to an air duct, the air duct is connected to a dust suction port, the dust suction port is directly opposite to the top of the chain grate, and the air inlet of the second induced draft fan is connected to a bag dust collector.

[0007] The principle and beneficial effect of the present invention are as follows: the heat storage chamber concentrates the heat emitted from the periphery of the kiln head on the surface of the kiln head, and the heat in the heat storage chamber is passed to the small ball roller screen through the heat pipe and the heat pipe by the induced draft fan, so that the pellets on the small ball roller screen can be preheated, thereby reducing the subsequent drying and roasting heating time or heating temperature, achieving energy saving effect. The second induced draft fan can absorb the dust above the chain grate through the dust suction port, collect and recycle it, and reduce the unit consumption of products.

[0008] Solution 2, which is the preferred basic solution, the heat storage chamber includes a shell, a rib plate and a kiln head cover. The rib plate is welded to the outside of the kiln head cover, and the shell is welded to the outside of the rib plate. An air collecting plate is provided on one end of the heat storage chamber, and the air collecting plate is connected to the heat pipe. Due to the large volume of the heat storage chamber, the air suction efficiency is low when only the pipe port is used, and an air collecting plate is added to improve the air suction efficiency.

[0009] Option 3, which is the preferred option of the basic option, is to cast refractory materials on the heat pipe and the inner wall of the heat pipe. This can extend the service life of the pipe and reduce heat loss.

[0010] Scheme 4 is the preferred basic scheme. The ball roller screen is provided with a number of roller screen shafts. The roller screen shaft is a hollow shaft. A heat-conducting bearing is connected to one end of the roller screen shaft. The outer ring of the heat-conducting bearing is provided with a through hole for connecting the heat-conducting pipe. The end of the heat-conducting bearing facing the ball roller screen is not provided with a sealing structure. Since the roller screen shaft is rotating and each roller screen shaft is connected to a motor, the solid heat-conducting pipe cannot be directly connected to the roller screen shaft. The inner ring of the heat-conducting bearing is connected to the roller screen shaft, and the through hole is connected to the heat-conducting pipe. The end of the heat-conducting bearing facing the outside of the roller screen drum is sealed, and the end facing the roller screen drum is not sealed. The hot air can pass through the through hole, through the gap between the rollers, and blow into the roller screen drum. The problem of connecting the rotating roller screen shaft with the non-rotating pipe in the vertical direction is solved.

[0011] Solution 5 is the preferred basic solution. A U-shaped tube is provided on the heat-conducting bearing to connect the two heat-conducting bearings. The heat-conducting tube is connected to the roller screen shaft at the end of the ball roller screen closest to the grate. Hot air enters from one end of the ball roller screen, flows in one direction in the roller screen, and blows out from the other end of the ball roller screen. The temperature of the hot air decreases step by step in the ball roller screen, and the balls fall from the end with lower temperature onto the ball roller screen, and the preheating temperature increases step by step. The preheating effect is better.

[0012] Solution 6, this is the preferred basic solution. The heat pipes are connected to both sides of the ball roller screen respectively. The heat-conducting bearings are connected to the heat-conducting bearings of the roller screen shafts separated by a U-shaped tube. The installation positions of the heat-conducting bearings of every two adjacent roller screen shafts are staggered. The dual-channel fan has one air inlet and two air outlets. The hot air enters from both sides of the ball roller screen through the heat-conducting pipes. Each roller screen is evenly heated, and the transformation cost is low.

[0013] Solution 7, which is a preferred solution of Solution 6, the two roller screen shafts at the end of the small ball roller screen are respectively connected with air guide pipes, and the air guide pipes are connected to the air outlet of the second induced draft fan. The hot air in the small ball roller screen is blown out from the roller screen after heat exchange with the pellets and has become normal temperature air. This air is introduced into the air outlet of the second induced draft fan to supplement the air volume of the second induced draft fan.

[0014] Solution 8: The air outlet of the second induced draft fan is connected to a ring cooler through an air duct. The air duct is provided with a first branch pipe and a second branch pipe. The free end of the first branch pipe is directly opposite to the grate pressure transmitter, and the free end of the second branch pipe is directly opposite to the high temperature monitor. The ring cooler is used to cool the pellets roasted in the rotary kiln. One section of wind needs to cool the pellets from 1000°C to about 600°C. The wind passing through the small ball roller screen is close to room temperature and can be used to compensate for the cooling wind of the ring cooler. The first branch pipe and the second branch pipe can be used for dust removal on the surface of the grate pressure transmitter and cooling of the high temperature monitoring equipment, and the dust raised by the first branch pipe can be sucked away by the dust suction port to achieve circulation and further achieve energy saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a rotary kiln head waste heat utilization system for metallurgical pellet production of the present invention;

[0016] Figure 2 yes Figure 1 The enlarged view of point A in the middle;

[0017] Figure 3 The present invention is a schematic structural diagram of a heat-conducting bearing in a rotary kiln head waste heat utilization system for metallurgical pellet production.

[0018] Figure 4 This is a front view of a rotary kiln head waste heat utilization system for metallurgical pellet production according to the present invention;

[0019] Figure 5 It is a top view of a rotary kiln head waste heat utilization system for metallurgical pellet production of the present invention;

[0020] Figure 6 It is a schematic diagram of the structure of a heat circulation system in a rotary kiln head waste heat utilization system for metallurgical pellet production of the present invention;

[0021] Figure 7 It is a structural schematic diagram of a heat storage chamber in a rotary kiln head waste heat utilization system for metallurgical pellet production according to the present invention;

[0022] Figure 8 It is a schematic diagram of the structure of the wind circulation system of the rotary kiln head waste heat utilization system for metallurgical pellet production of the present invention;

[0023] Fig. 9 yes Figure 7 Enlarged view of point B in the middle. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below through specific embodiments:

[0025] The figure marks in the drawings of the specification include: 1-heat circulation system, 2-wind circulation system, 3-heat storage chamber, 31-rib plate, 32-shell, 33-wind collecting plate, 4-first induced draft fan, 5-heat conduction pipe, 6-ball roller screen, 61-roller screen shaft, 62-heat conduction bearing, 621-through hole, 63-U-shaped pipe, 7-second induced draft fan, 8-air conduction pipe, 81-first branch pipe, 82-second branch pipe, 9-dust suction port, 10-bag dust collector, 11-chain grate machine, 12-chain grate machine pressure transmitter, 13-ring cooler, 14-kiln head cover, 15-high temperature monitor.

[0026] Example

[0027] like Figures 1 to 9As shown: A rotary kiln head waste heat utilization system for metallurgical pellet production, including a heat circulation system 1 and an air circulation system 2, the heat circulation system 1 includes a heat storage chamber 3 and a first induced draft fan 4, the heat storage chamber 3 is connected to a heat conduction pipe 5, the heat storage chamber 3 is connected to the air inlet of the first induced draft fan 4 through the heat conduction pipe 5, the air outlet of the first induced draft fan 4 is connected to a small ball roller screen 6 through the heat conduction pipe 5, the air circulation system 2 includes a second induced draft fan 7, the second induced draft fan 7 is connected to an air guide pipe 8, the air guide pipe 8 is connected to a dust suction port 9, the dust suction port 9 is arranged directly above the chain grate 11, and the air inlet of the second induced draft fan 7 is connected to a bag dust collector 10. The heat storage chamber 3 includes a shell 32, a rib plate 31 and a kiln head cover 34. The rib plate 31 is welded to the outside of the kiln head cover 34, and the shell 32 is welded to the outside of the rib plate 31. An air collecting plate 33 is provided on one end face of the heat storage chamber 3, and the air collecting plate 33 is connected to the heat conducting pipe 5. The inner wall of the heat conducting pipe 5 is cast with refractory material. The ball roller screen 6 is provided with a plurality of roller screen shafts 61. The roller screen shaft 61 is a hollow shaft. A heat conducting bearing 62 is connected to one end of the roller screen shaft 61. The outer ring of the heat conducting bearing 62 is provided with a through hole 621 for connecting the heat conducting pipe. The end of the heat conducting bearing 62 facing the ball roller screen 6 is not provided with a sealing structure. The heat conducting bearing 62 is provided with a U-shaped tube 63 for connecting the two heat conducting bearings 62. The heat conducting pipe 5 is connected to the roller screen shaft 61 at the end of the ball roller screen 6 that is closest to the chain grate 11. The first induced draft fan 4 is a dual-channel fan. There are two heat-conducting pipes 5. The heat-conducting pipes 5 are respectively connected to the two sides of the ball roller screen 6. The heat-conducting bearing 62 is connected to the heat-conducting bearing 62 separated by a roller screen shaft 61 through a U-shaped tube 63. The installation positions of the heat-conducting bearings 62 of every two adjacent roller screen shafts 61 are staggered. The two roller screen shafts 61 at the end of the ball roller screen 6 are respectively connected to the air duct 8, and the air duct 8 is connected to the air outlet of the second induced draft fan 7. The air outlet of the second induced draft fan 7 is connected to the annular cooler 13 through the air duct 8. The air duct 8 is provided with a first branch pipe 81 and a second branch pipe 82. The first branch pipe 81 leads to the chain grate pressure transmitter 12, and the second branch pipe 82 leads to the high temperature monitor 15.

[0028] The implementation method of this embodiment is as follows: when the rotary kiln is working, the waste heat generated by the kiln head is collected by the heat storage chamber 3 on the surface of the kiln head cover 14, and the waste heat of the kiln head is transported to the small ball roller screen 6 through the first induced draft fan 4 and the heat pipe 5, and the heat absorption efficiency is improved by the wind collecting plate 33. The waste heat enters the small ball roller screen 6 through the heat-conducting bearing 62 at the end of the roller screen shaft 61, and the roller screen shaft 61 is connected through the U-shaped tube 63, so that the waste heat flows in the small ball roller screen 6 in an S shape, and the waste heat enters the small ball roller screen 6 from the roller screen shaft 61 at the lowest end and is blown out from the roller screen shaft 61 at the highest end, and the temperature decreases step by step during the flow process. The pellets move from the highest end to the lower end of the small ball roller screen 6, and in this process, the temperature of the pellets increases step by step. After the hot air passes through the ball roller screen 6 for heat exchange, it becomes normal temperature air and is blown out. The normal temperature air is introduced into the second induced draft fan 7 through the air guide 8. The normal temperature air is also introduced to the chain grate pressure transmitter 12 through the first branch pipe 81, which can remove dust from its surface to prevent iron crystal powder from affecting the reading accuracy of the chain grate pressure transmitter 13. The normal temperature air is passed to the surface of the high temperature monitor 15 through the second branch pipe 82 to cool it. Dust will be generated during dust removal and pellet production. The dust is sucked into the bag dust collector 10 through the dust suction port 9 at the upper end of the chain grate 11. The dust can be recycled to reduce the unit consumption of the product. The air filtered by the bag dust collector 10 and the normal temperature air after heat exchange with the ball roller screen 6 can be sent to the ring cooler 13 through the second induced draft fan 7 to supplement the air volume of the ring cooler 13.

[0029] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A rotary kiln head waste heat utilization system for metallurgical pellet production, characterized in that: The invention comprises a heat circulation system (1) and an air circulation system (2), wherein the heat circulation system (1) comprises a heat storage chamber (3) and a first induced draft fan (4), wherein the heat storage chamber (3) is connected to a heat conduction pipe (5), wherein the heat storage chamber (3) is connected to an air inlet of the first induced draft fan (4) via the heat conduction pipe (5), wherein an air outlet of the first induced draft fan (4) is connected to a small ball roller screen (6) via the heat conduction pipe (5), wherein the air circulation system (2) comprises a second induced draft fan (7), wherein the second induced draft fan (7) is connected to an air guide pipe (8), wherein the air guide pipe (8) is connected to a dust suction port (9), wherein the dust suction port (9) is arranged above a chain grate (11), and wherein the air inlet of the second induced draft fan (7) is connected to a bag dust collector (10).

2. The rotary kiln head waste heat utilization system for metallurgical pellet production according to claim 1, characterized in that: The heat storage chamber (3) includes a shell (32) and a rib plate (31), wherein the rib plate (31) is welded to the outside of the kiln head cover (14), and the shell (32) is welded to the outside of the rib plate (31). An air collecting plate (33) is provided on one end face of the heat storage chamber (3), and the air collecting plate (33) is connected to the heat conducting pipe (5).

3. The rotary kiln head waste heat utilization system for metallurgical pellet production according to claim 1, characterized in that The inner wall of the heat conducting pipe (5) is cast with refractory material.

4. The rotary kiln head waste heat utilization system for metallurgical pellet production according to claim 1, characterized in that: The ball roller screen (6) is provided with a plurality of roller screen shafts (61), each of which is a hollow shaft. One end of the roller screen shaft (61) is connected to a heat-conducting bearing (62), and the outer ring of the heat-conducting bearing (62) is provided with a through hole (621) for connecting a heat-conducting pipe. The end of the heat-conducting bearing (62) facing the ball roller screen (6) is not provided with a sealing structure.

5. The rotary kiln head waste heat utilization system for metallurgical pellet production according to claim 4, characterized in that: The heat-conducting bearing (62) is provided with a U-shaped tube (63) for connecting the two heat-conducting bearings (62). The heat-conducting tube (4) is connected to the roller screen shaft (61) at the end of the ball roller screen (6) closest to the chain grate (11).

6. A rotary kiln head waste heat utilization system for metallurgical pellet production according to claim 5, characterized in that The heat-conducting pipes (5) are respectively connected to (62), and the installation positions of the heat-conducting bearings (62) of every two adjacent roller screen shafts (61) are staggered.

7. A rotary kiln head waste heat utilization system for metallurgical pellet production according to claim 6, characterized in that The two roller screen shafts (61) at the ends of the ball roller screen (6) are respectively connected to air guide pipes (8), and the air guide pipes (8) are connected to the air outlet of the second induced draft fan (7).

8. The rotary kiln head waste heat utilization system for metallurgical pellet production according to claim 1, characterized in that The air outlet of the second induced draft fan (7) is connected to the ring cooler (13) through the air duct (8), and the air duct (8) is provided with a first branch pipe (81) and a second branch pipe (82), the free end of the first branch pipe (81) is facing the chain grate pressure transmitter (13), and the free end of the second branch pipe (82) is facing the high temperature monitor (15).

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